1. Field of the Invention
This invention is directed to a pool covering apparatus and particularly to an extendable and retractable swimming pool cover adapted with a braking system for controlling the rotational momentum of a clutch cover collecting drum and thereby insure that a uniform, compact roll is collected on the cover collecting drum.
2. State of the Art
The use of swimming pool covers on conventional and residential type swimming pools is well known. Pool covers are becoming standard equipment for maximizing pool safety as well as reducing unwanted debris from entering the swimming pool when it is not in use. In addition, the use of pool covers will minimize heat loss from pool waters and can also be used to utilize the sun's rays to heat the pool water during daylight hours.
Most motorized pool covering apparatus includes a recessed well or a raised housing positioned at one end thereof and having mounted therein an elongated drum fixed to a rotatable shaft which in turn is connected to an electric motor. An impervious flexible pool cover is secured, at one of its ends, to the cover collecting drum and is collectable thereon by rotational movement of the drum. The pool cover is extended over the top of the swimming pool by attaching draw cords to both sides of the pool cover as longitudinal extensions thereof, and extending the draw cords the length of the pool and around a pulley rotatably fixed to the other side thereof. The draw cord is returned and secured to a collecting reel which is rotatably carried on the same elongated shaft that carries the cover collecting drum. By energizing an electric motor, the draw cord collecting wheel is automatically slidably engaged to the rotatable shaft permitting the reel to rotate and collect the draw cord thereon. Rotation of the shaft and reel draws the pool cover over the length of the swimming pool and thereby covering same. To maintain the sides of the pool cover in close proximity to the side walls of the swimming pool, a slideway channal is fixed to each of the longitudinal side margins of the swimming pool for engaging a bead formed on the lateral side edges of the pool cover. The beads are formed by folding an elongated strip of the pool cover material or some other suitable sheet material such as canvas or Nylon fixed thereto over a portion of the extended draw cord and securing same thereto by stitching or other means. In so doing, the draw cord, collected on the draw cord collecting reel, becomes a longitudinal propagation of the bead. A beaded pool cover of the type just described is disclosed in U.S. Pat. Nos. 3,050,743 and 3,051,232 and are incorporated herein by reference.
In addition thereto, the above pool cover includes a unique braking system for controlling the tension applied to the pool cover during the extension and retraction sequence and thereby insures that the cover collected or released from the cover collecting drum will be uniform and compact during operation. Basically, this braking system comprises a spring biased pin or pins having a brake shoe fixed to one of its ends and mounted such that the brake shoe will frictionally contact one side or face of a draw cord collecting reel. The use of the above braking mechanism, adequately resolved problems associated with draw cord tangling and uncontrolled rotational movement of the cover collecting drum or the draw cord collecting reel. However, it was found that with the pool cover apparatus heretofore used certain difficulties arose in maintaining a constant and adjustable force on the cover collecting drum and as a result the cover roll collected on the cover collecting drum would be loose and uneven causing the pool cover to bias during the extension and retraction sequence.